The Covenant (The Bracken Covenant)

Dr. Carver, who is the head of the English department at Stanford University, would not be the most likely of men to embark on a mission to save a group of kidnapped kids from devil-worshiping zealots in an underground facility, but after trailing a suspected colleague, and witnessing a kidnapping first hand, his pursuit quickly lands him in an underground bomb shelter, renovated as a secret monastery for a cult that calls themselves "The Bracken Covenant." Dr. Carver and the group of kidnapped kids struggle to survive the horrors of the elaborate underground cultist den. Outnumbered and vulnerable, with the kids being easy targets for not just the demonic zealots, but the wretched, feral animal experiments that the zealots keep underground, Dr. Carver has to lead the kids through trial after trial of both man and beast to escape before the covenant can cave in the underground passages, trapping them inside a den of evil—doomed to share the same fate as the hundreds of tortured spirits that reside there.